See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

## Analysis of Functional Group Isomerism **Key Concept:** Functional isomers have the same molecular formula but different functional groups. **Checking each option:** **(A) Nitro alkane and alkyl nitrite** - Nitro alkane: $R-NO_2$ - Alkyl nitrite: $R-O-N=O$ - Same molecular formula, **different functional groups** → functional isomers ✓ **(B) Aldehydes and ketones** - Aldehyde: $R-CHO$ - Ketone: $R_2CO$ - Same molecular formula, **different functional groups** → functional isomers ✓ **(C) Alcohols and aldehydes** - Alcohol: $R-OH$ (e.g., $C_2H_6O$ as $CH_3CH_2OH$) - Aldehyde: $R-CHO$ (e.g., $C_2H_6O$ as $CH_3CHO$) - Wait — **both have molecular formula $C_nH_{2n+2}O$**, so they DO have the same formula and different functional groups → **these ARE functional isomers** - However, the question asks which are **NOT** functional isomers **Re-examination of (C):** Alcohols ($-OH$) and aldehydes ($-CHO$) represent **structural isomerism with different functional groups**, making them functional isomers by definition. **(D) Alcohols and ether (both saturated)** - Alcohol: $R-OH$ - Ether: $R-O-R'$ - Same molecular formula, **different functional groups** → functional isomers ✓ **Answer: (C)** is **incorrect as stated** in the problem. Alcohols and aldehydes ARE functional isomers (e.g., $CH_3CH_2OH$ and $CH_3CHO$ both have formula $C_2H_6O$). If (C) is marked correct, the question likely intends that option (C) lists compounds that don't fit the pattern of being functional isomers of each other in the typical sense expected.